1. Field of the Invention
The invention is concerned with an improved filter means internal of a hydraulic reservoir, which filter means includes baffle means which directs fluid from said filter means to egress into the reservoir only below a normal fluid level therewithin.
2. Prior Art
The prior art has primarily been concerned with filter elements which are of the spin on or thread on type and are attachable externally of a hydraulic system which contains a hydraulic fluid. Generally, flow is provided of the hydraulic fluid through such a filter element and then from that filter element to a sump or other hydraulic reservoir of the system. A typical prior art external filter element of this nature is disclosed for example in U.S. Pat. No. 3,685,658. Some prior art filter assembly of this nature have provided bypass flow which takes over in case of a clogging of the filter element. U.S. Pat. No. 3,374,892 for example discloses such a filter assembly. Some filter elements are also used within hydraulic reservoirs such as those disclosed in for example U.S. Pat. Nos. 3,0886,072 and 3,900,400 but these are of considerably different structure, operation and mounting than are the structures of the present invention.
It can be very desirable to place filter means for a hydraulic system within a hydraulic reservoir of the system so as to obtain more resistance to flow, protection of the filter elements from damage from external sources and the like. However, with such an internal filter means it has been found that it is necessary to ensure that excessive foaming of the hydraulic fluid does not occur as this fluid leaves the filter means and is introduced into the interior of the hydraulic reservoir. The present invention provides just such an internal filter means wherein foaming is prevented and, further, in preferred embodiments of the invention provides bypass valve means whereby hydraulic fluid is introduced to the reservoir generally via the filter means when the filter elements themselves are partially or completely clogged, which bypass valve directs the bypassing hydraulic fluid to be introduced in such a manner that foaming does not occur within the reservoir. These and other advantages of the invention as will become apparent by reading the following specification are accomplished as set out herein.